The production of renewable liquid fuels directly from biomass resources is of great importance in view of the present high consumption of fossil fuels. Today, about three quarters of the world's energy is provided by fossil fuels such as coal, oil, and natural gas. Fossil fuels, however, are nonrenewable resources. Diminishing reserves of fossil fuels and growing concerns about global warming call for sustainable sources of energy such as renewable liquid fuels.
A known method for producing liquid fuels from biomass entails fermentation of sugars to produce ethanol. Ethanol, however, is not a good candidate for a liquid fuel due to its low energy density (23 MJ/L), high volatility (BP 78° C.), and high solubility in water (fully miscible). Other liquid fuel candidates such as 2,5-dimethylfuran (DMF) and 2,5-dimethyltetrahydrofuran (DMTHF) which can be produced from renewable biomass therefore have gained interest.
It is known to use a two-step synthesis of 2,5-dimethylfuran (DMF) liquid fuel via 5-hydroxymethylfurfural (HMF) produced by dehydration of fructose. DMF, compared to ethanol, possesses higher energy density (31.5 MJ/L), lower volatility (BP 92-94° C.) and is immiscible with water. However, the application of this two-step synthesis is limited due to low yield and complicated separations. Moreover, a typical method for manufacture of HMF from cellulose entails either aqueous acid hydrolysis at high temperatures and pressures (250-400° C., 10 MPa) at less than 30% yield or using expensive ionic liquid as solvent.
Although methods for manufacture of biomass derived liquid fuels are known, these methods have numerous disadvantages as discussed above.
A need therefore exists for a method of generating renewable liquid fuels that addresses the disadvantages of the prior art.